Image processing apparatuses such as digital cameras and camera-equipped mobile telephones perform various types of image processing on image data, and the resulting image data is displayed on a display unit, or is outputted to the exterior.
Examples of image processing in an image processing apparatus include, for instance, reading image data from a memory, performing image processing, and storing the result again in the memory. To process a plurality of pixels in, for example, an instance of image processing such as a color correction process, the pixel values of a plurality of pixels stored in a memory are read out, are subjected to a correction process, and are stored again in the memory.
In a case where image processing using such a memory involves, for instance, sequential input of image frames, consistency in the sequence of image frames is not maintained by storing, in a memory, image data of a next frame, before reading image data of a previous frame that is stored in the memory.
In a case where, for instance, a plurality of image processes are carried out in a sequential pipe line, image data is read from the memory in order to carry out a next image process, before image data that has been processed is stored in the memory. Consistency in the image processing order is not maintained thereby.
If consistency in the order of image frames or the order of image processes is not maintained, there are instances where image data that is outputted after a final image process is abnormal, and thus consistency of the image data itself is not preserved.
Techniques for maintaining consistency in image data include, for instance, those disclosed in Japanese Laid-open Patent Publication No. 11-161776. For example, data coordinates are outputted to a checking unit in order to determine whether data having a coordinate identical to that of data to be processed is or not in a current process, and the operation of a pipeline processing unit is discontinued if the checking unit determines that the data coordinates inputted by the pipeline processing unit are in a current process.
However, the above-described determination technique that uses data coordinates involves determining whether or not data is in a current process for all the coordinate positions of the data. Accordingly, for instance, all the pixels in the inputted image data are monitored. In such a case, input of image data of a plurality frames involves determination for all the pixels of all the frames. The above-described technique, thus, incurs very substantial processing time and power consumption.